The skies over Beijing turned yellow and air pollution soared to severe levels as China suffered its worst dust storms in over a decade. The capital, Beijing, was entirely engulfed in clouds three times in the last five weeks with the visibility dropping to about half a mile. A giant cloud of sand and dust particles rolled into the city, propelled by strong winds from the north of China. The current storm, the worst in the series, is expected to continue in the coming days, affecting central and eastern China. The extreme conditions are believed to be the combination of air pollution and dust from Mongolia, which is suffering from a hot and dry spell of weather, being driven by unusually strong winds.

The dust storms reduced visibility, leading to transport disruptions. Hazardous driving conditions resulted in traffic congestion and an increase in accidents. Hundreds of flights were delayed at regional airports.

The air quality index in Beijing hit a “hazardous” 999 leading officials to order children, the elderly, and the sick to stay indoors and suggested all others to stop nonessential outdoor activities. The storms were not sandstorms but were, in fact, dust storms carrying much smaller particles that travel much further, remain suspended longer, and are more harmful to humans. The concentrations of harmful PM2.5 particles, particulate matter measuring 2.5 micrometers in diameter which is small enough to penetrate human lungs and enter the bloodstream, reached extremes as well. Frequent exposure to PM2.5 and “coarse” PM10, which is 10 micrometers wide and enters deep into the lungs, is tied to cardiovascular and respiratory diseases and lung cancer.